Low-temperature chemical synthesis of lead zirconate titanate (PZT) powders free from halides and organics

Abstract

A water-soluble peroxititanic complex [Ti(OH) 3 O 2 ] 2 was prepared through the reaction between titanium metal and hydrogen peroxide at pH~11. A solution of lead nitrate and zirconyl nitrate was added to the peroxititanic acid solution, and a stoichiometric and amorphous precipitate of a mixed oxide of lead, zirconium and titanium was formed, which was filtered off and washed to eliminate nitrate ions. The precipitate was calcined between 600 and 1000 uC using a closed alumina boat. The precipitate was characterized by TG-DTA, ICP (Pb, Zr and Ti), elemental analysis (C, H, N and O), Raman spectroscopy and X-ray diffraction (XRD), and the calcined PZT powders were characterized by Raman spectroscopy and XRD. The amorphous precipitate showed a weight loss of 26% in the range from 30 to 500 uC, revealing that the crystallization process starts at low temperature. Rhombohedral Pb(Zr 0.60 Ti 0.40 )O 3 was obtained at temperatures above 900 uC. It is of particular importance that the use of the peroxititanic complex provided a method to synthesize PZT powders without the use of any organics (including alkoxides) or reagents containing undesirable halides.

Structure and photocatalytic properties of Nb-doped Bi12TiO20 prepared by the oxidant peroxide method (OPM)

“…The outstanding features of the OPM powders are their reactivity, which could be confirmed in the SEM images of Fig. 4 by the presence of partially sintered particles and by the formation of necks between them (Camargo et al 2001(Camargo et al , 2004Nogueira et al 2014;Pinto et al 2011).…”

“…It is well known that the amorphous precipitate generated by the OPM route sometimes referred simply to as precursor is highly reactive and crystallizes at lower temperatures than those obtained by other routes (Camargo et al 2001(Camargo et al , 2004Nogueira et al 2014;Pinto et al 2011). Although pure sillenite Bi 12 TiO 20 phase was identified in the sample calcined at 700°C for 1 h, extra peaks were observed at 24°, 30°, 47°, and 57°in the XRD patterns of the Nbdoped samples (Fig.…”

“…Pure (Bi 12 TiO 20 ) and Nb-doped (Bi 12 Ti 1-x Nb x O 20 ) samples of bismuth titanate were prepared with x = 0.05 (BNT5), 0.10 (BNT10), and 0.15 (BNT15) through the dissolution of titanium metal powder (98 % Aldrich, USA) and NbCl 5 (99 %, Aldrich, USA) in an aqueous solution of 60 mL of H 2 O 2 (30 %, analytical grade, Synth, Brazil) and 40 mL of ammonia solution (30 %, analytical grade, Synth, Brazil) (Camargo et al 2001). After approximately 3 h, a yellow solution of peroxo complex was obtained.…”

“…The approaches for achieving this goal include the incorporation of transition metal ions into the semiconductor photocatalyst using various methods, such as ion implantation, sol-gel synthesis, solid-state reaction, and others (Zhang et al 2006;Yang et al 2002, Zhou et al 2007. In this context, the oxidant peroxide method (OPM) has been used to produce highly reactive ceramic powders with a variety of particle morphologies, sizes, and compositions (Camargo et al 2001(Camargo et al , 2004Nogueira et al 2014;Pinto et al 2011). A distinctive feature of OPM powders is the homogeneous distribution of elements throughout the entire particle Mendonça and Ribeiro 2011).…”

Synthesis of Nb Doped Lead Zirconate Titanate by Chemical Methods

“…The spectra of the calcined powders confirm the formation of the PZT perovskitic phase, showing the typical peaks (204, 274, 580, 738 cm -1 ). [21] In both cases (SD and SG powders), the best results in terms of sinterability were reached when powders were sintered at 1100°C for 2 h, Figure 6. The microstructures of SG and SD samples show dense structures with an homogenous distribution of big and small grains that justifies the transgranular fracture type observed in the fracture surfaces.…”